Dover.
Are we not getting off topic here? My reasons for dropping the Goldmund motor as a mule for my TT project will in no way advance this thread. It is an average motor with an above average speed measuring mechanism. Further you have described how it works. I only used it by way of example to back up my earlier assertion that high sample rates were used way back then. You are quite right, the sample rate and feedback loop bandwidth of two different things. It is probable that the samples are put thru several divider networks to bring the sample frequency down to a manageable level while simultaenously improving accuracy. (Other TT's of that era do this). I no longer have a circuit diagram so cannot confirm.
And yes, wavy lines on a PCB under a multi pole rotating magnet are one way of measuring speed. Their output count is exactly as I described. Still used today in our industry for their robustness and long term reliability.
Are we not getting off topic here? My reasons for dropping the Goldmund motor as a mule for my TT project will in no way advance this thread. It is an average motor with an above average speed measuring mechanism. Further you have described how it works. I only used it by way of example to back up my earlier assertion that high sample rates were used way back then. You are quite right, the sample rate and feedback loop bandwidth of two different things. It is probable that the samples are put thru several divider networks to bring the sample frequency down to a manageable level while simultaenously improving accuracy. (Other TT's of that era do this). I no longer have a circuit diagram so cannot confirm.
And yes, wavy lines on a PCB under a multi pole rotating magnet are one way of measuring speed. Their output count is exactly as I described. Still used today in our industry for their robustness and long term reliability.